Drum conveyor and method to rotate rod-shaped articles

ABSTRACT

The invention relates to a drum conveyor defining a drum rotational axis and an outer peripheral surface, the drum conveyor comprising: o a first seat and a second seat, each of the first seat and second seat being adapted to transport a rod-shaped article, the first seat and the second seat being located at the outer peripheral surface of the drum conveyor; o a first shaft and a second shaft, wherein the first shaft defines a first shaft longitudinal axis and the second shaft defines a second shaft longitudinal axis, the first shaft longitudinal axis and the second shaft longitudinal axis being substantially perpendicular to the drum rotational axis, the first seat being attached to the first shaft and the second seat being attached to the second shaft, so that a rotation of the first shaft around the first shaft longitudinal axis and of the second shaft around the second shaft longitudinal axis cause the first seat and the second seat to rotate; o a pusher coupled with the first shaft and the second shaft by mechanical coupling, the pusher being adapted to linearly move along a pusher direction and engage with the first shaft and second shaft while moving; o an actuator adapted to move the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis so as to rotate the first shaft and the second shaft and the attached first seat and second seat at the same time. The invention also relates to a method to rotate rod-shaped articles.

The present invention relates to a drum conveyor to rotate a rod-shaped article and a method to rotate a rod-shaped article.

Aerosol generating articles, for instance, filter cigarettes, typically comprise a rod of tobacco cut filler surrounded by a paper wrapper and a cylindrical filter aligned in end-to-end relationship with the wrapped tobacco rod and attached thereto by tipping paper. Several filters for smoking articles are known that comprise a plurality of cylindrical components attached in axial alignment. By way of example, methods are known for manufacturing a filter for a smoking article comprising two or three different segments.

In the manufacture of such multi-component filters, one or more of the components may be initially provided as a double or quadruple length component, that is, a component which is two or four times the length of that component in the final smoking article. These multiple-length rods are typically cut and separated into smaller portions and other components may be introduced between the cut portions. The various segments within a filter must usually be placed in a particular order and arrangement, such that consecutive segments are in abutting relationship or aligned with one another at a predetermined distance from each other, for example to define an internal cavity of the filter.

Distinct filter components may be, during processing, moved by a linear conveyor, such as a driving chain. Thus, the linear conveyor is adapted to convey the filter segments along a first conveyance direction which extends substantially parallel to an axial direction of the components themselves.

Furthermore, additional objects may be introduced inside the filters. Filters may include flavorant capsules, threads, heating elements, susceptors and others. The positioning of such elements inside the filter components is important for the quality of the finished product.

For example, the incorrect positioning of an object in a component that is cut may damage the object. For example, in case the object is a susceptor, the impact of the blade used for such cuts may change the susceptor's shape, which may impair the functionality of the susceptor during to use.

Furthermore, the incorrect position of an object in a component may alter the sensorial experience of a user, and the consistency of the finished product.

Typically, during manufacture of aerosol generating articles, the end of the rod needs to be inspected, for example to verify the density of the tobacco, the porosity of the rod, or the position of an object in a component. However, this is difficult where the rods are transported in an end-to-end relationship. Therefore, there is a need for a system and a method to rotate rod-shaped components, which are reliable in rotating but at the same time do not require a relatively complex assembly.

According to an aspect, the invention relates to a drum conveyor defining a drum rotational axis and an outer peripheral surface. Preferably, the drum conveyor comprises a first seat and a second seat, each of the first seat and second seat being adapted to transport a rod-shaped article, the first seat and the second seat being located on the outer peripheral surface of the drum conveyor. Preferably, the drum conveyor comprises a first shaft and a second shaft, wherein the first shaft defines a first shaft longitudinal axis and the second shaft defines a second shaft longitudinal axis, the first shaft longitudinal axis and the second shaft longitudinal axis being substantially perpendicular to the drum rotational axis, the first seat being attached to the first shaft and the second seat being attached to the second shaft, so that a rotation of the first shaft around the first shaft longitudinal axis and a rotation of the second shaft around the second shaft longitudinal axis cause the first seat and the second seat to rotate. Preferably, the drum conveyor comprises a pusher coupled with the first shaft and the second shaft by mechanical coupling, the pusher being adapted to linearly move along a pusher direction and engage with the first shaft and second shaft while moving. Preferably, the drum conveyor comprises an actuator adapted to move the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis so as to rotate the first shaft and the second shaft and the attached first seat and second seat at the same time.

In the drum conveyor of the invention, the seats formed on the outer cylindrical surface are constructed and arranged to receive rod-shaped articles. The seats are attached to shafts which can rotate around the shaft's longitudinal axis. Two shafts are forced into rotation by a linear movement of a pusher. The pusher in turn is moved by an actuator. The rotation of the shafts causes a rotation of the seats and thus a rotation of the rod-shaped articles housed in the seats. A simple mechanical construction with relatively few elements enables the rotation of the rod-shaped articles by any angle.

The drum conveyor defines a drum rotational axis around which the drum conveyor is adapted to rotate. The drum conveyor can be mechanically driven, for example by a drum drive comprising a gear or a toothed belt. The drum conveyor may be driven by an electrical drum drive. The drum conveyor is preferably cylindrically shaped and comprises an outer peripheral surface. The outer peripheral surface is for example a substantially cylindrical surface having as a geometrical centre the drum rotational axis.

The drum conveyor is adapted to transport and rotate rod-shaped articles. Each of the rod-shaped articles comprises an outer surface, preferably substantially cylindrical, which extends along a longitudinal axis. In case of substantially cylindrical rod-shaped articles, the longitudinal axis corresponds to the axis of the cylinder.

The drum conveyor comprises at least a first seat and a second seat located on the outer peripheral surface. In the following, when it is said that a characteristic applies to a “seat” without mentioning whether it is the first seat or the second seat, it means that it applies to both the first seat and the second seat. The seats are positioned at the outer peripheral surface. Each seat is adapted to hold a rod-shaped article during transport. The first seat extends longitudinally along a first seat axis and the second seat extends longitudinally along a second seat axis. Each of the first seat and second seat is adapted, as the drum conveyor rotates, to receive a rod-shaped article having its longitudinal axis parallel to the seat axis. Preferably, each seat is so configured that the rod-shaped article can be housed therein, when the seat axis and the longitudinal axis of the rod-shaped article are parallel, more preferably concentric. The seats may be adapted to house a single rod-shaped article, or more than one rod-shaped article. If more than one rod-shaped article is housed in the seat, the rod-shaped articles are preferably in abutment relationship with their longitudinal axes substantially aligned.

Preferably, the drum conveyor comprises more than two seats, for example N seats, where N>2, all positioned on the peripheral surface of the drum conveyor. More preferably, the seats are equally spaced apart about the periphery of the drum. Preferably, the drum conveyor comprises between 10 and 100 seats. More preferably, the drum conveyor comprises between 40 and 80 seats. In some embodiments, the drum conveyor comprises 50 seats.

Preferably, all seats present in the drum conveyor have the same geometrical shape. For example, each of the first seat and second seat comprises a receiving surface adapted to contact the outer surface of the rod-shaped article. The receiving surface preferably comprises a portion of a recessed surface, for example a cylindrical surface. The cylindrical surface has a diameter equal to or slightly bigger than the diameter of the rod-shaped article transported by the drum conveyor. The axis of the cylindrical surface, a part of which is the receiving surface, defines the seat axis.

Each seat preferably includes a suction aperture, connected to a suction system or pneumatic system, adapted to hold the rod-shaped article in the seat by suction while the drum conveyor rotates. More than an aperture may be present depending on the size and weight of the rod-shaped article.

The drum conveyor comprises a first shaft and a second shaft. In the following, when it is said that a characteristic applies to a “shaft” without mentioning whether it is the first shaft or the second shaft, it means that it applies to both the first shaft and the second shaft. The first shaft is adapted to rotate around a first shaft longitudinal axis and the second shaft is adapted to rotate around a second shaft longitudinal axis. The first shaft longitudinal axis and the second shaft longitudinal axis are both substantially perpendicular to the drum rotational axis of the drum conveyor. Preferably, the first shaft and the second shaft extend radially around the drum rotational axis. Preferably, the first shaft longitudinal axis and the second shaft longitudinal axis are coplanar. The first shaft is associated to the first seat and the second shaft is associated to the second seat. If N seats, with N>2, are present in the conveyor drum, then the number N of shafts comprised in the drum conveyor is the same as the number of N seats, so that each seat of the N seats is associated to a shaft of the N shafts. Preferably, to one seat, only one shaft is associated. In case of N shafts, with N>2, all shafts are adapted to rotate around a shaft longitudinal axis. The N longitudinal axes preferably are coplanar. The N shaft longitudinal axes are preferably all perpendicular to the drum rotational axis. The N shaft longitudinal axes extend preferably along radii of a circumference defined by sectioning the drum conveyor with a plane perpendicular to the drum rotational axis, the circumference having as a centre the drum rotational axis and as outer boundary the outer peripheral surface.

Each seat is attached to its associated shaft in such a way that a rotation of the shaft causes rotation of the seat. Therefore, for rotations, shaft and associated seat move as an integral body. Preferably, the seat is attached to the shaft in such a way that the shaft longitudinal axis and the seat axis are substantially perpendicular to each other.

Preferably, each shaft defines a first end and a second end, axially opposed to each other. The first end may face the drum rotational axis and the second end may be attached to the seat located at the outer peripheral surface. Preferably, the seat is fixed to the second end of the shaft.

Further, the drum conveyor comprises a pusher. Preferably, the pusher is rod-shaped. The pusher is adapted to linearly move along a pusher direction. Preferably, the pusher direction is not perpendicular to the drum rotational axis. Preferably, the pusher direction is substantially parallel to the drum rotational axis. “Linearly move” means that the pusher is adapted to perform linear movements, that is, movements along a substantially straight line. More preferably, the pusher is adapted to reciprocate along the pusher direction. Therefore, the pusher is adapted to perform a linear forward motion (forward movement) and a linear backward motion (backward movement).

The pusher is associated with the first shaft and the second shaft. In case of N shafts, where N>2, the drum conveyor preferably comprises N/2 pushers. Each pusher of the N/2 pushers is associated to two nearest neighbour shafts.

The pusher is adapted to engage with the first shaft and the second shaft by means of a mechanical coupling. Due to the mechanical coupling, the linear movement of the pusher is transformed into a rotational movement of the first shaft around the first shaft longitudinal axis and of the second shaft around the second shaft longitudinal axis. The pusher therefore converts the pusher linear motion into a rotational motion of the shafts.

Preferably, the mechanical coupling is adapted to rotate the first shaft and the second shaft in opposite direction. For example, the mechanical pusher forces the first shaft to rotate clockwise around the first shaft longitudinal axis and the second shaft to rotate counter-clockwise around the second shaft longitudinal axis, as a result of the pusher linear movement. Preferably, the direction of rotation of the first shaft or second shaft during the forward movement of the pusher is reversed during the backward movement of the pusher.

The mechanical coupling between the pusher and the first shaft and second shaft may be of any kind as long as the mechanical coupling is capable of the conversion of motion from linear to rotational. The mechanical coupling may be known in the art.

Preferably, the pusher is for example located between the first shaft and the second shaft. The first shaft and second shaft are preferably angularly spaced. In the space formed between the first shaft and second shaft, preferably the pusher is inserted. Preferably, the pusher is in contact with the first shaft and the second shaft.

In case of N shafts, with N>2, the first shaft and second shaft are nearest neighbour shafts. Nearest neighbour shafts are the shafts which are angularly the closest. In case of N shafts, with N>2, for each couple of nearest neighbour shafts a pusher is preferably inserted in between. For example, in case of a first shaft, a second shaft, a third shaft and a fourth shaft, a first pusher engages the first shaft and the second shaft, and a second pusher engages the third shaft and the fourth shaft. One shaft is preferably engaged with only one pusher.

In order to perform the linear movement, so that the first shaft rotates around the first shaft longitudinal axis and the second shaft rotate around the second shaft longitudinal axis, the pusher is put into motion by an actuator. The actuator pushes the pusher along the pusher direction to force the pusher to shift. The translation takes place along a translation vector having as a direction the pusher direction and a given modulus. The value of this modulus determines, among others, the angle of rotation of the first shaft and of the second shaft. Thus, depending on the actuator action on the pusher, the movements of the pusher along the pusher direction may have different amplitudes. “Amplitude” of the linear movement of the pusher means the modulus of the translation vector. The amplitude is thus the distance between the position of an end of the pusher at the beginning of the movement and the position of the same end of the pusher at the end of the movement, where the beginning and the end of the movement are two instants t1 and t2, with t2>t1, during the rotation of the drum conveyor around the drum rotational axis. The distance is calculated along the pusher direction. Preferably, the pusher direction is parallel to the drum rotational axis. During the rotation of the drum conveyor around the drum rotational axis, the linear movement of the pusher reaches a maximum amplitude, at the point in time when the pusher start to reverse the movement along the same pusher direction. The maximum amplitude of the movement is preferably comprised between 0.5 centimetres and 2 centimetres.

Preferably, the amplitude of the pusher movements is so selected that the rotation of the first shaft around the first shaft longitudinal axis and the rotation of the second shaft around the second shaft longitudinal axis, due to the pusher's linear movements, are of at least 80 degrees. Preferably, the selected amplitude is such that the rotation of the first shaft around the first shaft longitudinal axis and the rotation of the second shaft around the second shaft longitudinal axis, are substantially equal to 90 degrees. Rotations of 90 degrees allows an inspection of the ends, and in particular of the end surfaces, of a rod-shaped articles in an easy manner. Therefore, if an inspection system is present, accurate inspection of the ends of the rod-shaped articles may be possible.

Preferably, the action of the pusher on the first shaft and on second shaft changes during the rotation of the conveyor drum around the drum rotational axis, because preferably the pusher linear movements are reciprocating movements. Therefore, during rotation of the drum conveyor, the rotation of the first shaft and the second shaft may change as well.

Preferably, in a 360 degrees rotation of the drum conveyor around the drum rotational axis, the pusher performs a forward movement and a backward movement. Preferably, the forward movement and backward movement have the same maximum amplitude. A forward movement of the pusher is a linear movement of the pusher away from the actuator, and the backward movement is a linear movement of the pusher towards the actuator. Preferably, the pusher direction is parallel to the drum rotational axis. Therefore, a forward movement is a linear movement of the pusher parallel to the drum rotational axis having a first orientation, and a backward movement is a linear movement parallel to the drum rotational axis and having the opposite orientation to the first orientation.

Preferably, at one point in time during the rotation of the drum conveyor around the drum rotational axis, indicated with t=0, the first seat and the second seat have their first seat axis and the second seat axis substantially perpendicular to the drum rotational axis. When the drum conveyor starts rotating, the actuator acts on the pusher pushing the pusher to make the forward movement. The resulting linear movement rotates the first shaft and second shaft thanks to the mechanical coupling. During rotation of the drum conveyor, therefore, the pusher moves along the pusher direction till the pusher movement reaches the maximum amplitude. Preferably, this maximum amplitude is such that, when reached, the first shaft has been rotated around the first shaft longitudinal axis and the second shaft has been rotated around the second shaft longitudinal axis by an angle of at least 90 degrees and more preferably substantially equal to 90 degrees. In this configuration where the rotation is of 90 degrees, preferably, the seat axes of the first seat and second seat are substantially parallel to the drum rotational axis.

When this configuration has been reached, that is, when a rotation of the first shaft longitudinal axis and of the second shaft longitudinal axis by 90 degrees are obtained, the action of the actuator on the pusher changes and the backward movement of the pusher starts, reversing its linear forward movement. This reverse movement causes a change in the rotation direction of the first shaft around the first shaft longitudinal axis and second shaft around the second shaft longitudinal axis. If during the forward movement of the pusher, the first shaft is rotating clockwise and the second shaft is rotating counter-clockwise, during the backward movement of the pusher, the rotations of the first shaft and second shaft become counter-clockwise and clockwise, respectively. The maximum amplitude of this backward movement is preferably the same as the maximum amplitude of the forward movement and therefore, preferably, the first shaft and second shaft are again rotated by 90 degrees. At the end of the backward movement, thus, the seat axes are again substantially perpendicular to the drum rotational axis.

Preferably, at one point in time during the rotation of the drum conveyor around the drum rotational axis, indicated with t=0, the first seat and the second seat have their first seat axis and the second seat axis forming an angle equal to α with the drum rotational axis. When the drum conveyor starts rotating, the actuator acts on the pusher pushing the pusher to make the forward movement. The resulting linear movement rotates the first shaft and second shaft thanks to the mechanical coupling. During rotation of the drum conveyor, therefore, the pusher moves along the pusher direction till the pusher movement reaches the maximum amplitude. Preferably, this maximum amplitude is such that, when reached, the first shaft has been rotated around the first shaft longitudinal axis and the second shaft has been rotated around the second shaft longitudinal axis by an angle β for which the seat axes of the first seat and second seat are substantially parallel to the drum rotational axis. Thus preferably α+β=90 degrees.

When this configuration has been reached, that is, when a rotation of the first shaft longitudinal axis and of the second shaft longitudinal axis by β degrees are obtained, the action of the actuator on the pusher changes and the backward movement of the pusher starts, reversing its linear forward movement. This reverse movement causes a change in the rotation direction of the first shaft around the first shaft longitudinal axis and second shaft around the second shaft longitudinal axis. If during the forward movement of the pusher, the first shaft is rotating clockwise and the second shaft is rotating counter-clockwise, during the backward movement of the pusher, the rotations of the first shaft and second shaft become counter-clockwise and clockwise, respectively. The maximum amplitude of this backward movement is preferably the same as the maximum amplitude of the forward movement and therefore, preferably, the first shaft and second shaft are again rotated by β degrees. At the end of the backward movement thus the seat axes are again substantially forming an angle equal to α with the drum rotational axis.

During the forward and backward movements, at each point in time, the angle formed between the seat axis and the drum rotational axis is dependent on the position of the pusher along the pusher direction. For example, the forward movement of the pusher comprises a movement from a first position to a second position along the pusher direction. In the first position, the angle between the seat axis and the drum rotational axis may be of 90 degrees, while in the second position, the angle between the seat axis and the drum rotational axis may be of 0 degrees. While the pusher moves between the first position and the second position, the angle formed between the seat axis and the drum rotational axis is between 0 degrees and 90 degrees, the exact value depending on the exact instantaneous position of the pusher.

With the above construction, the rotation of the seats, and thus of the rod-shaped articles which are positioned in the seats, is relatively simple and requires relatively few mechanical parts. A smaller drum conveyor may thus be used, which in turn allows to save energy due for example to the relatively low inertia when compared to a bigger drum conveyor. Furthermore, the angle of rotation of the longitudinal axis of the rod-shaped article can be easily determined by changing the maximum amplitude of the linear movement of the pusher. Any angle of rotation can be easily achieved. A simple and effective selection of the angle is achieved. The drum conveyor of the present invention is thus adapted to more effectively and smoothly change the orientation of a filter rod article.

Preferably, the pusher direction is perpendicular to the first shaft longitudinal axis or to the second shaft longitudinal axis. Having the pusher direction perpendicular to the shaft longitudinal axis, allows a stable and efficient mechanical coupling between the pusher and the first shaft and second shaft.

Preferably, the actuator comprises a cam, the cam pushing the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis. Relative rotations between the pusher and the cam are transformed into the linear movement of the pusher. In this configuration, the pusher acts as the follower of the cam. The pusher preferably rotates integral with the drum conveyor, so that rotations of the drum conveyor correspond to rotation of the pusher around the same axis (the drum rotational axis). Preferably, the cam is an end cam. Preferably, the drum conveyor comprises a first wall and a second wall, located at two opposite sides of the outer peripheral surface. Preferably the cam is defined by a portion of the first wall. Namely, the first wall is preferably provided with the cam. Preferably, on a surface of the first wall, more preferably the surface facing the second wall, the cam is formed as a local thickness variation of the first wall. The first wall comprises a peripheral contour and the contour of the first wall changes thickness according to a predetermined pattern, so that the local distance along the drum rotational axis between the first wall and second wall changes. The pusher preferably defines a first end and a second end. The first end of the pusher preferably abuts against the cam. Preferably, the second end of the pusher is fixed to the second wall of the drum conveyor. In a preferred embodiment, the first wall including the cam is stationary, that is, the first wall does not rotate together with the drum conveyor when the drum conveyor rotates around the drum rotational axis. On the contrary, preferably, the second wall and the pusher rotate integral with the drum conveyor. Preferably, therefore, there is a relative rotation between the first wall and the second wall. When the drum conveyor rotates, the first end of the pusher slides onto the surface of the first wall (or the surface of the first wall slides on the first end of the pusher) defining the cam and follows the contour of the surface of the first wall. Due to the variations in thickness of the first wall, the surface on which the pusher slides, is not flat but includes “protrusions” that push the pusher towards the second wall. This pushing force causes the linear movement of the pusher towards the second wall. The amplitude of the linear movement depends on the difference between a first distance and a second distance. A first distance is the distance between the point of the surface of the first wall where the pusher is in contact to and the corresponding point on an inner surface of the second wall facing the first wall calculated along an axis parallel to the drum rotational axis at the beginning of the movement. The second distance is the distance between the point of the surface of the first wall where the pusher is in contact to and the corresponding point on an inner surface of the second wall facing the first wall calculated along an axis parallel to the drum rotational axis at the end of the linear movement. The bigger the difference is, the bigger the amplitude. The shape of the surface of the first wall is conformed in such a way that after a rotation of substantially less or equal to 180 degrees of the drum conveyor around the drum rotational axis, the rotation of the first shaft around the first shaft longitudinal axis or the rotation of the second shaft around the second shaft longitudinal axis is of at least 80 degrees, more preferably of at least 90 degrees.

Preferably, the first wall is stationary. Preferably, the cam stays stationary and the pusher slides on it while the drum conveyor rotates. The pusher, integral in rotations with the drum conveyor, slides on the cam and it is thus forced to perform the linear movement along the linear direction, due to the cam shape. The movement of the pusher is preferably substantially that of a follower of an end cam.

Preferably, the pusher comprises a first end and a second end, and the first end of pusher is adapted to engage with the actuator. Preferably, the action of the actuator is performed on one of the opposite first and second distal ends of the pusher, for example on the first end. For example, the actuator is a cam and the pusher its follower, so that the first end of the pusher slides on the cam in a relative rotation of the pusher and cam.

Preferably, the pusher is provided with an elastic element. More preferably, the elastic element exerts an elastic force on the pusher towards the first wall. Preferably, a force is exerted on the pusher so that the first end of the pusher remains in engagement with the actuator. Preferably, this force is an elastic force. Preferably, this force has a major component towards the first wall. The elastic force may be generated by an elastic element provided at the second end of the pusher. The elastic element generates a force preferably directed along the pusher direction. Preferably, this elastic force has an orientation opposite to the orientation of the force exerted by the actuator on the pusher. The elastic force may bias the first end of the pusher to remain engaged with the actuator. For example, when the first end of the pusher slides on the surface of the first wall, the second end of the pusher may be engaged with an elastic element which pushes the pusher towards the surface of the first wall, so that contact can be maintained between the first end of the pusher and the surface of the first wall comprising the cam. Preferably, the elastic element is compressed between the pusher and the second wall. Preferably, the elastic element is connected to the second wall. The elastic element may for example include a spring. The elastic element may comprise a block of elastic material, such as rubber. The elastic element may be mounted so that it is always in a compressed state, so that it exerts the elastic force on the pusher towards the first wall constantly. The elastic force varies when the pusher is moved linearly. The elastic force increases when the pusher is moved along the pusher direction towards the second wall. Preferably, the pusher direction is parallel to the drum rotational axis and the first end of the pusher engages with the actuator while the second end of the pusher engages with the elastic element. The force exerted by the actuator on the pusher has a component along the pusher direction. The elastic force exerted by the elastic element on the pusher has a component along the pusher direction.

Preferably, the elastic element is adapted to bias the pusher towards the cam for maintaining a contact between the pusher and the cam. In order to maintain the contact between pusher and cam during the rotation of the drum conveyor, a force is needed. This force may be provided by the elastic element. Preferably, the pusher slides on the surface of the first wall while the contact is kept during the relative rotation between the first wall and the pusher by the force exerted by the elastic element. Preferably, the elastic element is positioned between the second wall and the second end of the pusher.

Preferably, the pusher is telescopic and comprises an inner tubular element and an outer tubular element, the inner tubular element being slidable in the outer tubular element along the pusher direction. The telescopic pusher may change the pusher total length along the pusher direction, from a minimum length in a contracted configuration to a maximum length in an extended configuration. Preferably, the telescopic pusher is pushed towards the extended configuration by the elastic force exerted by the elastic element. The actuator pushes the telescopic pusher towards the contracted configuration. The reciprocate movements of the pusher therefore include extensions and retractions of the telescopic pusher. The maximum amplitude of the linear movement is therefore the difference in total length of the pusher between the total length in the extended configuration of the pusher and the total length in the contracted configuration of the pusher. The linear movements are thus sliding movements of the inner tubular element in and out the outer tubular element. Preferably, the elastic element may be located between the inner tubular element and the outer tubular element and the elastic element is compressed when the inner tubular element is sliding in the outer tubular element.

Preferably, the mechanical coupling between the first shaft and second shaft and the pusher comprises a rack and a pinion. Preferably, in order to transform the linear movement of the pusher into a rotational movement of the first shaft and second shaft, a mechanical coupling that comprises a circular gear (the pinion) engaging a linear gear (the rack) is used. Driving the rack linearly causes the pinion to be driven into a rotation. This configuration of the mechanical coupling is very efficient in the transformation of the motion and relatively simple to realize. However, other mechanical coupling may be used as well.

Preferably, the pusher comprises a first rack and a second rack, and the first shaft comprises a first pinion and the second shaft comprises a second pinion; the pusher being positioned so that the first rack engages with the first pinion and the second rack engages with the second pinion. Preferably, the pusher is located between the first shaft and the second shaft. The exact position of the insertion of the pusher between the first shaft and the second shaft, for example the distance between the pusher and the drum rotational axis, depends on the position of the pinions formed in the first shaft and second shaft. Preferably, the pusher includes a first rack and a second rack. The first rack and the second rack may face opposite directions. The first rack may face the first shaft and the second rack may face the second shaft. The first rack may engage with the first pinion. The second rack may engage with the second pinion. In this way, a linear movement of the first rack and of the second rack, due to the engagement of the first rack and the second rack with the first pinion and the second pinion, respectively, is transformed into a rotational movement of the first shaft and a rotational movement of the second shaft. Due to the fact that the first seat is attached to the first shaft and the second seat is attached to the second shaft, the rotational movements of the first shaft and the second shaft also correspond to a rotation of the first seat around the first shaft longitudinal axis and of the second seat around and of the second shaft longitudinal axis.

Preferably, the linear movement of the pusher defines an amplitude and wherein the amplitude is so selected that the first seat and the second seat rotate at least of 90 degrees. The pusher direction is preferably parallel to the drum rotational axis. Preferably, the pusher direction is perpendicular to the first shaft longitudinal axis and the second shaft longitudinal axis. Preferably, the linear movement includes a forward movement and a backward movement. Preferably the forward movement and the backward movement are both included within a single rotation of the drum conveyor by 360 degrees. Preferably, the forward movement and the backward movement have the same maximum amplitude. Preferably, at a given point in time t1 during the rotation the seat axes are substantially perpendicular to the drum rotational axis. After a rotation of the drum conveyor less or equal to 180 degrees, at a point in time t2, where t2>t1, preferably the seat axes are parallel to the drum rotational axis. After a subsequent rotation of the drum conveyor before or upon completing a full rotation, the seat axes are preferably again perpendicular to the drum rotational axis.

Preferably, the drum conveyor comprises a plurality of N seats and a plurality of N shafts, and N/2 pushers, wherein each k-th, where k=1 . . . N/2, pusher of the N/2 pusher is coupled to two nearest neighbour shafts (i, i+1), where i=1, 3, 5 . . . N−1 according to the above aspect. Preferably, in the drum conveyor, the number of pusher is half the number of shafts (or seat). Therefore, if the number of seats and shafts is equal to N, the number of pushers is equal to N/2. The coupling between one pusher with two shafts allows to rotate N shafts using only N/2 pushers. The N shafts are preferably all perpendicular to the drum rotational axis. Preferably, the N shafts are coplanar. Each shaft of the N shafts is associated to a seat of the N seat. Preferably, the association is the same as the association between the first seat and the first shaft and the second seat and the second shaft. Each of the N/2 pusher is coupled to two nearest neighbour shafts of the N shafts. The relationship between shafts and pushers is thus preferably the following.

The k-th pusher, where k is an integer from 1 to N/2, is coupled to two nearest neighbour shafts, called i-th shaft and (i+1)-th shaft, where i is an odd integer from 1 to N−1. Thus, between the first shaft and the second shaft a first pusher is interposed, between the second shaft and a third shaft there is no pusher, between the third shaft and a fourth shaft a second pusher is interposed and so on.

Preferably, the drum conveyor comprises N seats equally spaced around the outer peripheral surface of the drum conveyor. Preferably, the drum conveyor also comprises N shafts, a shaft associated to each seat of the N seats. Preferably, the N seats may have an uneven spacing. For example, the spacing between two nearest neighbour seats associated to two shafts between which a pusher is inserted may be different from the spacing between two nearest neighbour seats associated to two shafts between which a pusher is not present. Furthermore, the spacing among seats may not correspond to the spacing among the rod-shaped articles positioned in the seats.

According to a further aspect, the invention relates to a system for turning rod-shaped articles, the system comprising a drum conveyor according to the previous aspect. The rod-shaped article is rotated by a predefined angle in the drum conveyor. Preferably, the rod-shaped article is rotated from a configuration in which its longitudinal axis is perpendicular to the drum rotational axis to a configuration in which its rotational axis is substantially parallel to the drum rotational axis.

The advantage of this system has been already outlined with reference to the first aspect and not herewith repeated.

Preferably, the system further comprises an inspection apparatus adapted to inspect rod-shaped articles positioned on the first seat or on the second seat (or both on the first seat and the second seat). If rod-shaped articles are transported in a conveying direction with the longitudinal axes of articles parallel to the conveying direction, it may be difficult to inspect the end surfaces of the rod-shaped articles. The inspection of one or more of the end surfaces of a rod-shaped article may be relevant to assess the quality of the rod-shaped article. For example, it is desired to examine the presence of deformations, such as ovality, of the rod-shaped article. It may be desirable, in case an object is inserted in the rod-shaped article during manufacture, to assess whether the location of the object is correct. However a path of rod-shaped articles travelling one after the other with their axes parallel to each other may render this task difficult.

Therefore, in order to inspect the first end or the second end of the rod-shaped article, particularly when the rod-shaped articles are positioned in the seats of the drum conveyor initially with the rod longitudinal axis perpendicular to the drum rotational axis, it is preferred to use the system of the invention to rotate the rod-shaped article by a selected angle, for example by 90 degrees. The rotation by 90 degrees is a rotation of the longitudinal axis of the rod shaped article with respect to the initial direction of the longitudinal axis. Thus, the rotation is a rotation with respect to the transport direction. Preferably, the system includes an inspection apparatus to inspect the first end or the second end or both of the rod-shaped articles. Preferably, the inspection apparatus comprises a camera. Preferably, the inspection apparatus is adapted to detect the position of a susceptor in the first end or second end of the rod-shaped article.

Preferably, the first seat extends along a first seat axis and the second seat extends along a second seat axis, and the inspection apparatus is adapted to inspect the rod-shaped articles on the drum conveyor when the first seat axis and the second seat axis are parallel to the drum rotational axis. Preferably the inspection apparatus is inspecting the first end or the second end of the rod-shaped article when the rod-shaped article is positioned in the first seat or the second seat and the first seat axis or the second seat axis is parallel to the drum rotational axis.

Preferably, the system comprises a first linear conveyor, the first linear conveyor being adapted to convey a flow of rod-shaped article maintaining the orientation of the longitudinal axes of the rod-shaped articles in a first conveyance direction extending substantially perpendicular to the drum rotational axis; and wherein the drum conveyor is located downstream the first linear conveyor and adapted to engage the rod-shaped articles and to transport the rod-shaped articles while rotating their longitudinal axes. The rotation of the longitudinal axes is a rotation with respect to the transport direction of the drum conveyor. The system thus comprises a transfer station where the rod-shaped articles are transferred from the first linear conveyor to the drum conveyor. As mentioned, this configuration does not allow an easy inspection of the end surfaces of the rod-shaped articles. For this reason, the rod-shaped articles are preferably transferred from the linear conveyor to the drum conveyor of the invention, where the articles are rotated by a given angle.

Preferably, the system comprises a second linear conveyor, the second linear conveyor being adapted to convey a flow of rod-shaped articles maintaining the orientation of the longitudinal axes of the rod-shaped articles in a second conveyance direction extending substantially perpendicular to the drum rotational axis; and wherein the second linear conveyor is located downstream the drum conveyor and adapted to engage the rod-shaped articles received from the drum conveyor. Thus, the system preferably transfer the rod-shaped articles back from the drum conveyor to another linear conveyor so that the rod-shaped articles are again transported with their longitudinal axes parallel to each other.

According to a further aspect, the invention relates to a method to rotate rod-shaped articles having a longitudinal axis. Preferably, the method comprises: providing a drum conveyor defining a drum rotational axis and an outer peripheral surface. Preferably, the drum conveyor comprises: a first seat and a second seat located on the outer peripheral surface of the drum conveyor. Preferably, the drum conveyor comprises: a first shaft and a second shaft, wherein the first shaft defines a first shaft longitudinal axis and the second shaft defines a second shaft longitudinal axis, the first shaft longitudinal axis and the second shaft longitudinal axis being substantially perpendicular to the drum rotational axis, the first seat being attached to the first shaft and the second seat being attached to the second shaft. Preferably, the drum conveyor comprises: a pusher forming a mechanical coupling with the first shaft and the second shaft. Preferably, the method comprises: positioning a rod-shaped article in the first seat and in the second seat. Preferably, the method comprises: rotating the drum conveyor around the drum conveyor rotational axis. Preferably, the method comprises: moving the pusher linearly along a pusher direction while rotating the drum conveyor. Preferably, the method comprises: transforming the linear movement of the pusher into a rotational movement of the first shaft around the first shaft longitudinal axis and of the second shaft around the second shaft longitudinal axis so as to rotate the longitudinal axes of the rod-shaped articles in the first seat and second seat.

The advantages of this aspect have been already described with reference to the previous aspects and not repeated herewith.

Preferably, the step of rotating the first shaft and the second shaft comprises: rotating the first shaft and the second shaft by 90 degrees. The rotation by 90 degrees allows to easily inspect the end surface of the rod-shaped article.

Preferably the step of rotating the first shaft and the second shaft comprises: rotating the first shaft and the second shaft in opposite directions. The pusher linear movement along a pusher direction is transformed into two rotational movements of the first shaft and the second shaft, respectively. For an easy transformation, the two rotational movements are in opposite directions.

Preferably, the step of the rotating the first shaft and the second shaft comprises: rotating the first shaft and the second shaft from a configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are perpendicular to the drum rotational axis to a configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis. It is preferred in some processing of the rod-shaped articles to position the rod-shaped articles in a row with their longitudinal axes parallel to each other and in an abutment relationship. However, in this configuration other processing step may be hindered, such as an inspection of the end surfaces of the rod-shaped articles. Preferably, the method of the invention rotates the rod-shaped articles from this initial configuration where the rod-shaped article are in a row to a configuration where the rod-shaped articles are rotated by 90 degrees. In this way, their end surfaces may be inspected easily.

Preferably, the step of rotating the drum conveyor comprises: rotating the drum conveyor around the drum rotational axis by 360 degrees. Preferably, in the same 360 degrees rotation of the drum conveyor, the step of rotating the first shaft and the second shaft comprises: rotating the first shaft and the second shaft from a configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are perpendicular to the drum rotational axis to a configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis; and rotating the first shaft and the second shaft from the configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis back to the configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis. As more processing steps on the rod-shaped articles are performed when the articles are positioned in a row with the longitudinal axes parallel to each other and in an abutment relationship, it is preferred to rotate “temporarily” the rod-shaped articles for a sufficient period of time for the desired inspection, and then rotate the articles back to the initial configuration.

Preferably, the method comprises inspecting the rod-shaped articles in the first seat and in the second seat when the first shaft and the second shaft are in the configuration where the longitudinal axes of the rod-shaped articles are parallel to the drum rotational axis. The inspection of the end surfaces may be facilitated in this configuration.

Preferably, the step of moving the pusher linearly along a pusher direction comprises: reciprocating the pusher along the pusher direction. The pusher may perform a forward movement in the first rotation of the first seat and the second seat by 90 degrees and a backward movement in the subsequent returning rotation of the first seat and the second seat by 90 degrees.

Preferably, the step of moving the pusher linearly along a pusher direction comprises: moving the pusher along the pusher direction by means of a cam. The relationship between the pusher and the cam is that the pusher acts as the follower of the cam.

Preferably, the step of providing a conveyor drum includes: providing a conveyor drum having a first wall and a second wall; and forming the cam in the first wall. A simple construction with few parts may be achieved.

Preferably, the step of providing a conveyor drum having a pusher includes: providing a telescopic pusher comprising an inner tubular element and an outer tubular element. Preferably, the step of moving the pusher linearly along a pusher direction includes: sliding the inner tubular element inwardly or outwardly the outer tubular element. The linear movement of the pusher may include sliding movement of a telescopic pusher changing the pusher total length along the pusher direction.

Preferably, the method comprises the step of: transferring one or more rod-shaped article from a first conveyor to the drum conveyor. More preferably, the first conveyor is a linear conveyor and the method includes: transporting a plurality of rod-shaped articles along a path with their axis parallel to each other.

In the following, the term “rod-shaped article” may refer to any element which may be included in an aerosol-forming article. Such elements are known in the art and not further detailed below. For example, such rod-shaped article might include a plug of a filter, a heat source, a tobacco rod, a charcoal element and so on. Preferably, the rod-shaped article is a plant material containing article, in particular a tobacco containing article. The tobacco article might contain a tobacco cut filler or an aerosol-forming reconstituted tobacco. The article may comprise a tobacco rod to be combusted or heated. Rod-shaped articles according to the invention may be whole, assembled aerosol-forming articles or elements of aerosol-forming articles that are combined with one or more other components in order to provide an assembled aerosol-forming article for producing an aerosol, such as for example, the consumable part of a heated smoking device.

Preferably, the element of the aerosol-forming article comprises a tobacco-containing material including volatile tobacco flavour compounds, which are released from an aerosol-forming substrate upon heating.

Preferably, the rod-shaped article may include a heat source, or a volatile flavour generating component, for example a menthol capsule, a charcoal element, or a susceptor.

The susceptor may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptors comprise a metal or carbon. A preferred susceptor may comprise a ferromagnetic material, for example ferritic iron, or a ferromagnetic steel or stainless steel. A suitable susceptor may be, or comprise, aluminium. Preferred susceptors may be formed from 400 series stainless steels, for example grade 410, or grade 420, or grade 430 stainless steel. Different materials will dissipate different amounts of energy when positioned within electromagnetic fields having similar values of frequency and field strength. Thus, parameters of the susceptor such as material type, length, width, and thickness may all be altered to provide a desired power dissipation within a known electromagnetic field.

Preferred susceptors may be heated to a temperature in excess of 250 degrees Centigrade. Suitable susceptors may comprise a non-metallic core with a metal layer disposed on the non-metallic core, for example metallic tracks formed on a surface of a ceramic core. A susceptor may have a protective external layer, for example a protective ceramic layer or protective glass layer encapsulating the elongate susceptor.

The susceptor may comprise a protective coating formed by a glass, a ceramic, or an inert metal, formed over a core of susceptor material.

Preferably, the rod-shaped article may have a length of between about 5 millimetres and about 20 millimetres, preferably between about 8 millimetres and about 16 millimetres for example of about 12 millimetres in length. In some cases, the rod-shape article may have a length of about 40 millimetres to about 85 millimetres.

In the following, the term “length”, unless otherwise specified, refers to a length of the rod-shaped article along its longitudinal axis.

In the following, the term “rod-shaped” denotes a generally cylindrical element of substantially cylindrical, oval or elliptical cross-section. However, other prismatic forms with different cross sections are also possible.

As used herein, aerosol-forming article is any article that generates an inhalable aerosol when an aerosol-forming substrate is heated. The term includes articles that comprise an aerosol-forming substrate that is heated by an external heat source, such as an electric heating element. An aerosol-forming article may be a non-combustible aerosol-forming article, which is an article that releases volatile compounds without the combustion of the aerosol-forming substrate. An aerosol-forming article may be a heated aerosol-forming article, which is an aerosol-forming article comprising an aerosol-forming substrate that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol. The term includes articles that comprise an aerosol-forming substrate and an integral heat source, for example a combustible heat source.

Aerosol-forming articles according to the present invention may be in the form of filter combustible cigarettes or other smoking articles in which tobacco material is combusted to form smoke.

Preferably, the aerosol-forming article may be substantially cylindrical in shape. The aerosol-forming article may be substantially elongated. The aerosol-forming article may have a length and a circumference substantially perpendicular to the length. The aerosol-forming article may have a total length between about 30 millimetres and about 100 millimetres. The aerosol-forming article may have an external diameter between about 5 millimetres and about 12 millimetres.

The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1: A drum conveyor defining a drum rotational axis and an outer peripheral surface, the drum conveyor comprising:

-   -   a first seat and a second seat, each of the first seat and         second seat being adapted to transport a rod-shaped article, the         first seat and the second seat being located on the outer         peripheral surface of the drum conveyor;     -   a first shaft and a second shaft, wherein the first shaft         defines a first shaft longitudinal axis and the second shaft         defines a second shaft longitudinal axis, the first shaft         longitudinal axis and the second shaft longitudinal axis being         substantially perpendicular to the drum rotational axis, the         first seat being attached to the first shaft and the second seat         being attached to the second shaft, so that a rotation of the         first shaft around the first shaft longitudinal axis and a         rotation of the second shaft around the second shaft         longitudinal axis cause the first seat and the second seat to         rotate;     -   a pusher coupled with the first shaft and the second shaft by         mechanical coupling, the pusher being adapted to linearly move         along a pusher direction and engage with the first shaft and         second shaft while moving;     -   an actuator adapted to move the pusher along the pusher         direction while the drum conveyor rotates around the drum         rotational axis so as to rotate the first shaft and the second         shaft and the attached first seat and second seat at the same         time.

Example Ex2: The drum conveyor according to Ex1, wherein the pusher direction is perpendicular to the first shaft longitudinal axis or to the second shaft longitudinal axis.

Example Ex3: The drum conveyor according to Ex1 or Ex2, wherein the actuator comprises a cam, the cam pushing the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis.

Example Ex4: The drum conveyor according to Ex3, wherein the drum conveyor comprises a first wall and a second wall, located at two opposite sides of the outer peripheral surface, and wherein the cam is defined by a portion of the first wall.

Example Ex5: The drum conveyor according to Ex4, wherein the first wall is stationary.

Example Ex6: The drum conveyor according to one or more of the preceding Ex1-Ex5, wherein the pusher comprises a first end and a second end, and the first end of pusher is adapted to engage with the actuator.

Example Ex7: The drum conveyor according to one or more of the preceding Ex1-Ex6, wherein the pusher is provided with an elastic element.

Example Ex8: The drum conveyor according to Ex7 when dependent on Ex4 or Ex5, wherein the elastic element exerts an elastic force on the pusher towards the first wall.

Example Ex9: The drum conveyor according to Ex7 or Ex8 when dependent on Ex3 or Ex4, wherein the elastic element is adapted to bias the pusher towards the cam for maintaining a contact between the pusher and the cam.

Example Ex10: The drum conveyor according to one or more of the preceding Ex1-Ex9, wherein the pusher is telescopic and comprises an inner tubular element and an outer tubular element, the inner tubular element being slidable in the outer tubular element along the pusher direction.

Example Ex11: The drum conveyor according to one or more of the preceding Ex1-Ex10, wherein the mechanical coupling between the first shaft and second shaft and the pusher comprises a rack and a pinion.

Example Ex12: The drum conveyor according to Ex11, wherein the pusher comprises a first rack and a second rack, and the first shaft comprises a first pinion and the second shaft comprises a second pinion; the pusher being positioned so that the first rack engages with the first pinion and the second rack engages with the second pinion.

Example Ex13: The drum conveyor according to one or more of the preceding Ex1-Ex12, wherein the linear movement of the pusher defines an amplitude and wherein the amplitude is so selected that the first seat and the second seat rotate at least of 90 degrees.

Example Ex14: The drum conveyor according to one or more of the preceding Ex1-Ex13, comprising a plurality of N seats and a plurality of N shafts, and N/2 pushers, wherein each k-th, where k=1 . . . N/2, pusher of the N/2 pusher is coupled to two nearest neighbour shafts (i, i+1), where i=1, 3, 5 . . . N−1 according to one or more of the preceding claims.

Example Ex15: The drum conveyor according to one or more of the preceding Ex1-Ex14, comprising N seats, the N seats being equally spaced around the outer peripheral surface of the drum conveyor.

Example Ex16: A system for turning rod-shaped articles, the system comprising:

-   -   a drum conveyor according to any one of Ex1 to Ex15;     -   an inspection apparatus adapted to inspect rod-shaped articles         positioned on the first seat or on the second seat.

Example Ex17: The system according to Ex16, wherein the first seat extends along a first seat axis and the second seat extends along a second seat axis, and wherein the inspection apparatus is adapted to inspect the rod-shaped articles on the drum conveyor when the first seat axis and the second seat axis are parallel to the drum rotational axis.

Example Ex18: A method to rotate rod-shaped articles having a longitudinal axis, the method comprising:

-   -   providing a drum conveyor defining a drum rotational axis and an         outer peripheral surface, the drum conveyor comprising:         -   a first seat and a second seat located on the outer             peripheral surface of the drum conveyor;         -   a first shaft and a second shaft, wherein the first shaft             defines a first shaft longitudinal axis and the second shaft             defines a second shaft longitudinal axis, the first shaft             longitudinal axis and the second shaft longitudinal axis             being substantially perpendicular to the drum rotational             axis, the first seat being attached to the first shaft and             the second seat being attached to the second shaft;         -   a pusher forming a mechanical coupling with the first shaft             and the second shaft;     -   positioning a rod-shaped article in the first seat and in the         second seat;     -   rotating the drum conveyor around the drum conveyor rotational         axis;     -   moving the pusher linearly along a pusher direction while         rotating the drum conveyor;     -   transforming the linear movement of the pusher into a rotational         movement of the first shaft and of the second shaft around the         first shaft longitudinal axis and the second shaft longitudinal         axis so as to rotate the longitudinal axes of the rod-shaped         articles in the first seat and second seat.

Example Ex19: The method according to Ex18, wherein the step of rotating the first shaft and the second shaft comprises:

-   -   rotating the first shaft and the second shaft by 90 degrees.

Example Ex20: The method according to Ex18 or Ex19, wherein the step of rotating the first shaft and the second shaft comprises:

-   -   rotating the first shaft and the second shaft in opposite         directions.

Example Ex21: The method according to Ex19 or Ex20, wherein the step of rotating the first shaft and the second shaft comprises:

-   -   rotating the first shaft and the second shaft from a         configuration where the longitudinal axes of the rod-shaped         articles in the first seat and in the second seat are         perpendicular to the drum rotational axis to a configuration         where the longitudinal axes of the rod-shaped articles in the         first seat and in the second seat are parallel to the drum         rotational axis.

Example Ex22: The method according to claim Ex20 or Ex21, wherein the step of rotating the drum conveyor comprises:

-   -   rotating the drum conveyor around the drum rotational axis by         360 degrees; and

-   wherein, in the same 360 degrees rotation of the drum conveyor, the     step of rotating the first shaft and the second shaft comprises:     -   rotating the first shaft and the second shaft from a         configuration where the longitudinal axes of the rod-shaped         articles in the first seat and in the second seat are         perpendicular to the drum rotational axis to a configuration         where the longitudinal axes of the rod-shaped articles in the         first seat and in the second seat are parallel to the drum         rotational axis;     -   rotating the first shaft and the second shaft from the         configuration where the longitudinal axes of the rod-shaped         articles in the first seat and in the second seat are parallel         to the drum rotational axis back to the configuration where the         longitudinal axes of the rod -shaped articles in the first seat         and in the second seat are parallel to the drum rotational axis.

Example Ex23: The method according to claim Ex21 or Ex22, comprising:

-   -   inspecting the rod-shaped articles in the first seat or in the         second seat when the first shaft and the second shaft are in the         configuration where the longitudinal axes of the rod-shaped         articles are parallel to the drum rotational axis.

Example Ex24: The method according to one or more of from Ex18 to Ex23, wherein the step of moving the pusher linearly along a pusher direction comprises:

-   -   reciprocating the pusher along the pusher direction.

Example Ex25: The method according to one or more of from Ex18 to Ex24, wherein the step of moving the pusher linearly along a pusher direction comprises:

-   -   moving the pusher along the pusher direction by means of a cam.

Example Ex26: The method according to one or more from Ex18 to Ex25, wherein the step of providing a conveyor drum includes:

-   -   providing a conveyor drum having a first wall and a second wall;     -   forming the cam in the first wall.

Example Ex27: The method according to one or more of from Ex18 to Ex26, wherein the step of providing a conveyor drum having a pusher includes:

-   -   providing a telescopic pusher comprising an inner tubular         element and an outer tubular element;

-   and wherein the step of moving the pusher linearly along a pusher     direction includes:     -   sliding the inner tubular element inwardly or outwardly the         outer tubular element.

Example Ex28: The method according to one or more of from Ex18 to Ex27, comprising the step of:

-   -   transferring one or more rod-shaped article from a first         conveyor to the drum conveyor.

Example Ex29: The method according to Ex28, wherein the first conveyor is a linear conveyor and the method includes:

-   -   transporting a plurality of rod-shaped articles along a path         with the longitudinal axes of the rod-shaped articles parallel         to each other.

Examples will now be further described with reference to the figures in which:

FIG. 1 is a schematic lateral view with some elements removed of a conveyor drum realized according to the invention;

FIG. 2 is a perspective view with some more elements removed of the conveyor drum of FIG. 1 ;

FIG. 3 is an enlarged view of a detail of FIG. 1 or 2 ;

FIG. 4 and FIG. 5 are perspective views in a dismounted configuration of another detail of the conveyor drum of FIGS. 1-2 in an extended configuration and in a contracted configuration, respectively;

FIG. 6 is a schematic perspective view in a dismounted configuration of another detail of the drum conveyors of FIGS. 1-2 ;

FIG. 7 is a perspective view of a system to inspect rod-shaped articles according to the invention, with some elements removed for clarity; and

FIG. 8 and FIG. 9 are perspective views of different details of FIG. 7 , with some elements removed for clarity.

With reference to FIGS. 1-3 and 9 , a conveyor drum adapted to rotate rod-shaped articles is globally indicated with 1.

A rod-shaped article 2 suitable to be transported and rotated by the conveyor drum 1 is visible in a simplified form in FIG. 3 . The rod-shaped article 2 includes a first end 3 and a second end 4 and defines a longitudinal axis 5. Furthermore, the rod-shaped article 2 includes an outer surface 6, substantially cylindrical.

The conveyor drum 1 is adapted to rotate around a drum rotational axis 7. The conveyor drum includes an outer peripheral surface 8, substantially cylindrical in shape and having as a centre the drum rotational axis 7. The conveyor drum 1 includes a first wall 9 and a second wall 10, facing each other and positioned at the two opposite sides of the outer peripheral surface 8. First wall 9 is stationary, that is, it does not rotate together with the rest of the conveyor drum 1 around the drum rotational axis 7, while second wall 10 rotates integral to the rest of the conveyor drum. The outer peripheral surface 8 has been removed from the drum conveyor 1 in FIG. 1 to better show the structure underneath.

Conveyor drum 1 includes a plurality of seats, preferably N seats with N≥2. Among the seats, which are preferably all having the same geometrical shape, a first seat and a second seat are indicated with 12 and 13, respectively. First seat 12 and second seat 13 are nearest neighbour seats. All N seats, including first seat 12 and second seat 13, are located at the outer peripheral surface 8 and are equally spaced around the outer peripheral surface 8. Each seat of the plurality is adapted to hold and transport at least one rod-shaped article 2, as visible for example in FIGS. 2 and 9 . In the following, all elements of the conveyor drum, if not mentioned otherwise like for the first wall 9, such as the outer peripheral surface 8 and the N seats, are integral in rotation with the second wall 10, thus when drum conveyor 1 rotates, these elements of the conveyor drum rotate as well around the drum rotational axis 7.

With reference to FIG. 3 , an enlarged view of the first seat 12 and second seat 13 is shown. In order to hold the rod-shaped article 2 while transporting the same, preferably each seat of the plurality includes an aperture 14 connected to a pneumatic system (not shown in the drawings). The pneumatic system, via aperture 14, is adapted to perform a suction action on the rod-shaped article 2 positioned in the seat. Each seat also includes a receiving surface 15 in contact with the outer surface 6 of the rod-shaped article 2, when the rod-shaped article 2 is transported in the seat. The receiving surface 15 is at least partially curved, for example it comprises a cylindrical surface, and it defines a seat axis. The seat axis is parallel to the longitudinal axis 5 of the rod-shaped article 2 when the rod-shaped article is transported in the seat. As depicted, the seat axis of the first seat 12 is indicated with 16 and the seat axis of the second seat 13 is indicated with 17.

The drum conveyor 1 comprises a plurality of shafts. The number of shafts is equal to the number of seats. To each shaft, a seat is associated. The drum conveyor 1 thus comprises a first shaft 18 and a second shaft 19 associated respectively with first seat 12 and second seat 13. Shafts are better visible in FIGS. 8 and 9 . Each shaft is adapted to rotate around a shaft longitudinal axis. The first shaft 18 is thus adapted to rotate around a first shaft longitudinal axis 20 and the second shaft 19 is adapted to rotate around a second shaft longitudinal axis 21. The shaft longitudinal axes of all shafts are perpendicular to the drum rotational axis 7. Each shaft longitudinal axis extends along a radius of the circumference defined by a cross section of the drum conveyor 1 taken along a plane perpendicular to the drum rotational axis 7. Each shaft further defines a first end 22 and a second end 23, the first end 22 being attached to the seat. The attachment between seat and shaft is such that rotations of the shaft around the shaft rotational axis correspond to rotations of the seat axis around the shaft rotational axis. Preferably, shaft rotational axis and seat axis are perpendicular to each other.

Further, each shaft comprises a pinion. With now reference to FIGS. 4 and 5 where only the first shaft 18 and second shaft 19 are shown, first shaft 18 comprises first pinion 24 and second shaft 19 comprises second pinion 25. First pinion 24 and second pinion 25 are integral in rotation with first shaft 18 and second shaft 19, respectively. Therefore, the first pinion 24 and second pinion 25 are adapted to rotate around the first shaft longitudinal axis 20 and second shaft longitudinal axis 21, respectively.

The drum conveyor 1 comprises a plurality of pushers, all indicated with 26. Each pusher is interposed between two nearest neighbour shafts. As shown in detail in FIGS. 1, 4 and 5 , pusher 26 is interposed between the first shaft 18 and the second shaft 19. The pusher 26 is rod-shaped and it comprises a first end 27 and a second end 28. The first end 27 is in abutment to the first wall 9, while the second end 28 is attached to the second wall 10. The second end 28 is integral in rotations with the second wall 10, while the first end 9 can slide on the first wall 9. The pusher 26 also defines a pusher direction 29, which preferably corresponds to the longitudinal axis of the pusher. Preferably the pusher direction 29 is parallel to the drum rotational axis 7. The pusher 26 is telescopic and includes an outer tubular member 30 and an inner tubular member 31, the inner tubular member 31 being slidable inside the outer tubular member 30 along the pusher direction 29. The pusher 29 therefore has a first extended configuration where the inner tubular member 31 is outside the outer tubular member 30 for a given length L1, so that the total length of the pusher 26 along the pusher direction 29 is at its maximum, and a second contracted configuration where the inner tubular member 31 is outside the outer tubular member 30 for a given length L2 with L2<L1 so that the total length of the pusher 26 along the pusher direction is at its minimum (see FIG. 1 ). The pusher 26 is adapted to perform linear movement, and more particularly reciprocation movement, along the pusher direction 29, moving from the contracted configuration depicted in FIG. 5 to the extended configuration depicted in FIG. 4 , and vice versa.

With now reference to FIGS. 1 and 6 , the drum conveyor 1 further includes a cam 32. Cam 32 is defined by the first wall 9. Cam 32 is preferably an end cam. Cam 32 comprises a rim portion 33 of the first wall 9 having a variable thickness. The rim portion 33 faces second wall 10. The rim portion 33 comprises ridges 34 and valleys 35. Thus the distance between a point in the rim portion 33 and the second wall 10 along a direction parallel to the drum rotational axis 7 changes depending on where in the rim portion this point is located, for example whether this point is located in the ridges 34 or in the valleys 35. The distance between a point on the rim portion 33 and the second wall 10 goes from a minimum, for example on the peak of a ridge, to a maximum, for example on the bottom of a valley. In the schematic lateral view of FIG. 1 , the difference in the total length of the pusher 26 when the first end 27 is on top of a ridge 34 or on the bottom of a valley 35 is exaggerated in order to show it clearly.

The pusher 26 has its first end 27 in abutment to the first wall 9 and in particular to the rim portion 33 and extends parallel to the drum rotational axis 7. Therefore, when the first end 27 is in abutment to the point of the rim portion 33 at the minimum distance (top of ridge 35) to the second wall 10, the pusher 26 is in the contracted configuration of FIG. 5 . When the first end 27 is in abutment to the point of the rim portion 33 at the maximum distance (bottom of valley 35) to the second wall 10, the pusher 26 is in the extended configuration of FIG. 4 .

The difference between the maximum distance and the minimum distance between points on the rim portion 33 and the second wall 10 is equal to the amplitude of the movement of the pusher 26 along the pusher direction 29.

The drum conveyor 1 further comprises a spring 40, preferably a spring for each pusher 9. The spring 40 is inserted on the inner tubular element 31 of the pusher 9 in a compressed state at the second end 28 of the pusher 26. Due to the compressed state, the spring 40 biases the pusher 26 toward an extended configuration, exerting an elastic force directed along the pusher direction 29 towards the first wall 9.

With reference back to FIGS. 4 and 5 , the pusher 26 comprises a first rack 36 and a second rack 37. First rack 36 faces the first shaft 18 while second rack 37 faces the second shaft 19. More in detail, the first rack 36 engages the first pinion 24 and the second rack 37 engages the second pinion 25. Due to the rack/pinion engagement, during the linear movement of the pusher 26 from the contracted configuration to the extended configuration or vice versa, the first pinion 24 and second pinion 25 are forced into rotation. The first shaft 18 and the second shaft 19 in turn rotate around the first shaft longitudinal axis 20 and the second shaft longitudinal axis 21.

The functioning of the drum conveyor 1 is as follow, with now reference back to FIGS. 1-3 . At time t=0, the first seat 12 and second seat 13 are arranged on the outer peripheral surface 8 so that the first seat axis 16 and the second seat axis 17 are perpendicular to the drum rotational axis 7. This configuration is shown in FIG. 2 considering as first seat 12 and second seat 13 two seats on the left side of the figure (indicated by the t=0 label). In this configuration, the pusher 26 is in the contracted configuration of FIG. 5 because the first end 27 of the pusher 26 is in contact with a peak of a ridge 34. As soon as the rotation of the drum conveyor 1 around the drum rotational axis 7 starts, the pusher 26 is transported in rotation together with the drum conveyor 1 (with the exception of the first wall 9) and the first end 27 of the pusher 26 slides on the rim portion 33, which remains stationary. The point of contact between the first end 27 of the pusher 26 and the rim portion 33 moves from ridge 34 towards valley 35. The contact between the first end 27 and the rim portion 33 is maintained thanks to the elastic force exerted by the spring 40 urging the first end 27 in abutment against the rim portion 33. Moving down the valley 35 allows the spring 40 to push the pusher 26 towards the first wall and the inner tubular element 31 slides outside the outer tubular element 30, increasing the total length of the pusher 26. The relative sliding of the inner tubular element 31 and outer tubular element 30 causes the linear movement of the first rack 36 and second rack 37 engaged in the first pinion 24 and second pinion 25, respectively. First shaft 18 and second shaft 19 thus rotates around the first rotational axis 20 and the second rotational axis 21. The first shaft 18 and the second shaft rotate 19 in opposite directions. For example, the first shaft 18 rotates clockwise, while the second shaft rotates counter-clockwise 19. This causes a rotation of the first seat axis 16 and the second seat axis 17.

While the rotation of the drum conveyors 1 continues, the first end 27 of the pusher 26 continues to slide on the rim portion 33 till the bottom of the valley 35 is reached. In this configuration, the total length of the pusher 26 is at its maximum, the pusher is in the extended configuration of FIG. 4 . In this extended configuration, the first shaft 18 and the second shaft 19 have been rotated by 90 degrees so that the first seat axis 16 and the second seat axis 17 are both parallel to the drum rotational axis 7. This configuration is depicted in the right portion of the drum conveyor in FIG. 2 (indicated with t=t1).

Preferably, after the rotation of 90 degrees has been obtained, while the drum conveyor 1 continues to rotate, the first end 27 of the pusher 26 continues to slide on the rim portion 33 and leaves the valley 35 to reach another ridge 34. Another rotation by 90 degrees of the first shaft 18 and second shaft 19 takes place, so that at the end of a 360 degrees rotation of the drum conveyor 1, the first seat 12 and second seat 13 have again the first seat axis 15 and second seat axis 16 perpendicular to the drum rotational axis 7.

The drum conveyor 1 can be used in a system 100 for the inspection of one or both of the first end 3 and second end 4 of the rod-shaped article 2.

With initial reference to FIG. 7 , the system 100 includes a first conveyor drum and a second conveyor drum, each of the first conveyor drum and second conveyor drum being constructed as described with reference to FIGS. 1-6 and 9 . In order to differentiate the first conveyor drum and the second conveyor drum, they are referred to 1 and 50, respectively, although they are both constructed identically to the conveyor drum identified with 1 described above. Each of the first conveyor drum 1 and the second conveyor drum 50 comprises a plurality of seats on the outer peripheral surface 8 of the conveyor drum and rotate around its first drum rotational axis 7 or second drum rotational axis 70, respectively. Each seat of the plurality extends longitudinally along the seat axis. Each of the first conveyor drum 1 and second conveyor drum 50 is adapted, while rotating, to receive a rod-shaped article 2 at an input station 102 (for the first conveyor drum 1), 104 (for the second conveyor drum 50) and to convey the rod-shaped article 2 to an output station 103 (for the first conveyor drum 1), 105 (for the second conveyor drum 50).

The system 100 further includes a first linear conveyor 109 transporting the rod-shaped articles 2 along a first conveying direction 110. The first conveying direction 110 is indicated by an arrow in FIG. 7 . The first linear conveyor 109 is adapted to transport the rod-shaped articles 2 along a path where the orientation of the longitudinal axes 5 of the rod-shaped articles 2 is parallel to the first conveying direction 110. The rod-shaped articles 2 are positioned in the first linear conveyor 109 in a row one after the other and they can be in abutment relationship, or a gap may be present between two adjacent rod-shaped articles.

The system 100 further comprises a first transfer drum 101 adapted to rotate around a first drum axis 111. The first transfer drum 101 is adapted to transfer rod-shaped articles 2 conveyed in the first linear conveyor 109 to the first conveyor drum 1, and in particular to first input station 102, maintaining the longitudinal axes 5 of the rod-shaped articles 2 aligned with the first conveying direction 110 (transfer drum does not rotate the rod-shaped articles). The first conveyor drum 1 is adapted to transport the rod-shaped articles 2 received from the first transfer drum 101 at the first input station 102 to the first output station 103 while rotating around its first drum longitudinal axis 7. During rotation around its first drum rotational axis 7, the first conveyor drum 1 is adapted to rotate the longitudinal axes 5 of the transported rod-shaped articles 2 by 90 degrees so that the longitudinal axes 5 of the transported rod-shaped articles 2 become parallel to the first drum rotational axis 7 at the first output station 103. The system 100 further comprises an inspection drum 112 adapted to rotate around an inspection drum axis 113 and to receive rod-shaped-articles 2 at the first output station 103 conveyed by the first conveyor drum 1. The inspection drum 112 can receive the rod-shaped articles 2 when the rod-shaped articles 2 have their longitudinal axes 5 parallel to the drum rotational axis 7. The transfer of the rod-shaped articles 2 takes place at the output station 103. Further, the inspection drum 112 is adapted to maintain the longitudinal axes 5 orientation unchanged. The system 100 further comprises a second conveyor drum 50 adapted to receive the rod-shaped articles 2 from the inspection drum 112 at the second input station 104 and to rotate the longitudinal axes 5 of the rod-shaped articles 2, while rotating around the second drum rotational axis 70, by 90 degrees so that the longitudinal axes 5 of the rod-shaped articles 2 are parallel again to the first conveying direction 110 when the rod-shaped articles 2 reaches the second output station 105. The system 100 further comprises a second transfer drum 130 and a second linear conveyor 140. The second transfer drum 130 is adapted to rotate around a second drum axis 131. The second transfer drum 130 is adapted to transfer rod-shaped articles 2 conveyed by the second conveyor drum 50 at the second output station 105 to the second linear conveyor 140. The second transfer drum 130 is also adapted to maintain the orientation of the longitudinal axes 5 of the rod-shaped articles 2 identical to the orientation they had at the second output station 105. Therefore, when the transfer to the second linear conveyor 140 takes place, the longitudinal axes 5 of the rod-shaped articles 2 are aligned with the first conveying direction 110.

The second linear conveyor 140 transports the rod-shaped articles 2 along a second conveying direction 141 indicated by an arrow in FIG. 7 . The second conveying direction 141 is preferably parallel to the first conveying direction 110. The second linear conveyor 140 is adapted to transport the rod-shaped articles 2 along a path where the orientation of the longitudinal axes 5 of the rod-shaped articles 2 is parallel to the second conveying direction 141. The rod-shaped articles 2 are positioned in the second linear conveyor 141 in a row one after the other and they can be in abutment relationship, or a gap may be present between two adjacent rod-shaped articles.

The system further comprises an inspection device 150 to inspect the first end 3 or the second end 4, or both of the rod-shaped articles 2. The inspection device 150 may include one or more cameras. The inspection device 150 is positioned at the inspection drum 112, preferably at one side of the inspection drum. In the inspection drum, preferably the ends 3, 4 of the rod-shaped articles 2 are inspected.

The first transfer drum 101 and second transfer drum 130 are known in the art. Preferably, they are substantially identical to each other. Each one of the first transfer drum 101 and second transfer drum 130 includes a plurality of flutes, all indicated with 107, which are adapted to engage with the rod-shaped articles 2. The first transfer drum 101 rotates around the first drum axis 111 which is preferably perpendicular to the first conveying direction 110 and the second transfer drum rotates around second drum axis 131, also perpendicular to the first conveying direction 110. The flutes 107 are so designed to hold the rod-shaped articles 2 with the longitudinal axes 5 in substantial alignment with the first conveying direction 110 during their rotation.

As the first transfer drum 101 rotates about its first drum axis 111, the flutes 107 holding the rod-shaped articles 2 reach the first input station 102 for the first conveyor drum 1. The rod-shaped articles 2 are thus delivered to the first conveyor drum 1 still with their longitudinal axes 5 parallel to the first conveyor direction 110. This transfer is depicted in the enlarged view of FIG. 9 . Only few element of the first conveyor drum 1 are depicted for clarity purpose. In order to obtain a transfer, the first conveyor drum 1 is mounted with respect to the first transfer drum 101 so that at the first input station 102, the first seat 12 and the second seat 13 of the first conveyor drum 1 receiving the rod-shaped articles 2 have their first seat axis 16 and second seat axis 17 parallel to the first conveyor direction 110. First drum axis 111 and drum rotational axis 7 are parallel to each other. The transfer between first transfer drum 101 and first conveyor drum 1 is known in the art and not further detailed herewith.

As already detailed, in the rotation of the first conveyor drum 1 around the drum rotational axis 7, the first seat 12 and second seat 13 rotate and therefore also the longitudinal axes 5 of the rod-shaped articles present in the first seat and second seat rotate. When the longitudinal axes of the rod-shaped articles 2 reaches a configuration where they are parallel to the drum rotational axis 7, the rod-shaped articles 2 are transferred to the inspection drum 112. This transfer is depicted in detail in FIG. 2 . The inspection drum 112 includes a plurality of inspection flutes 114 configured to keep the rod-shaped articles 2 with their longitudinal axes 5 perpendicular to the first conveying direction 110 which in turn means that their longitudinal axes 5 are parallel to the inspection drum axis 113. The inspection flutes 114, each of which receives a rod-shaped article 2, preferably have the geometrical shape of notches formed on a disc (the inspection drum), so that there is no element covering the first end and second end of the rod-shaped articles.

During the rotation of the inspection drum 112, the first end 3 or the second end 4 or both of the rod-shaped articles 2 located in the inspection flutes 114 pass in front of the inspection device 150 (not shown in FIG. 2 ). Preferably, the inspection device 150 is located at one or both sides of the inspection drum 112 to inspect the status of the first end 3 or second end 4 of the rod-shaped articles 2. Due to the orientation of the longitudinal axes 5 of the rod-shaped articles 2 in the inspection flutes 114, the first end 3 or second end 4 faces the inspection device 150 and thus inspection is relatively easy.

As the inspection drum 112 rotates about its inspection drum axis 113, the inspection flutes 114 holding the rod-shaped articles 2 reaches the second input station 104 to be transferred to the second conveyor drum 50. The rod-shaped articles 2 are thus delivered to the second conveyor drum 50 with their longitudinal axes 5 perpendicular to the first conveying direction 110. This transfer is depicted in the enlarged view of FIG. 8 . Only few element of the second conveyor drum 50 are depicted for clarity purpose. In order to obtain a transfer, the second conveyor drum 50 is mounted with respect to the inspection drum 112 so that at the second input station 104, the first seat 12 and the second seat 13 of the second conveyor drum 50 receiving the rod-shaped articles 2 have their first seat axis 16 and second seat axis 17 perpendicular to the first conveying direction 110. Inspection drum axis 113 and second drum rotational axis 70 are parallel to each other.

During the rotation of the second conveyor drum 50 around the second drum rotational axis 70, the first seat 12 and second seat 13 rotate and therefore also the longitudinal axes 5 of the rod-shaped articles 2 present in the first seat and second seat rotate. When the longitudinal axes 5 of the rod-shaped articles 2 reach a configuration where they are perpendicular to the second drum rotational axis 70, the rod-shaped-articles 2 are transferred to the second transfer drum 130, at second output station 105. This transfer is depicted in detail in FIG. 8 . The second transfer drum 130 includes a plurality of flutes 107 configured to keep the rod-shaped articles 2 with their longitudinal axes 5 parallel to the first conveying direction 110 which in turn mean perpendicular to the second drum axis 131. The flutes 107, each of which receives a rod-shaped article, preferably have the same shape of the flutes in the first transfer drum 101.

From the second transfer drum 130, the rod-shaped articles 2, oriented with their longitudinal axes 5 parallel to the first conveying direction 110 are transferred in a known manner to the second linear conveyor 140. The second linear conveyor 140 conveys the rod-shaped articles 2 without changing their orientation along the second conveying direction 141, parallel to the first conveying direction.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ±10 percent of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A represents. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. 

1. A drum conveyor defining a drum rotational axis and an outer peripheral surface, the drum conveyor comprising: a first seat and a second seat, each of the first seat and second seat being adapted to transport a rod-shaped article, the first seat and the second seat being located at the outer peripheral surface of the drum conveyor; a first shaft and a second shaft, wherein the first shaft defines a first shaft longitudinal axis and the second shaft defines a second shaft longitudinal axis, the first shaft longitudinal axis and the second shaft longitudinal axis being substantially perpendicular to the drum rotational axis, the first seat being attached to the first shaft and the second seat being attached to the second shaft, so that a rotation of the first shaft around the first shaft longitudinal axis and a rotation of the second shaft around the second shaft longitudinal axis cause the first seat and the second seat to rotate; a pusher coupled with the first shaft and the second shaft by mechanical coupling, the pusher being adapted to linearly move along a pusher direction and engage with the first shaft and second shaft while moving; an actuator adapted to move the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis so as to rotate the first shaft and the second shaft and the attached first seat and second seat at the same time.
 2. The drum conveyor according to claim 1, wherein the actuator comprises a cam, the cam pushing the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis.
 3. The drum conveyor according to claim 2, wherein the drum conveyor comprises a first wall and a second wall, located at two opposite sides of the outer peripheral surface, and wherein the cam is defined by a portion of the first wall.
 4. The drum conveyor according to claim 3, wherein the first wall is stationary.
 5. The drum conveyor according to claim 1, wherein the pusher comprises a first end and a second end, and the first end of pusher is adapted to engage with the actuator.
 6. The drum conveyor according to claim 1, wherein the pusher is provided with an elastic element.
 7. The drum conveyor according to claim 5, wherein the actuator comprises a cam, the cam pushing the pusher along the pusher direction while the drum conveyor rotates around the drum rotational axis, and wherein the elastic element is adapted to bias the pusher towards the cam for maintaining a contact between the pusher and the cam.
 8. The drum conveyor according to claim 1, wherein the pusher is telescopic and comprises an inner tubular element and an outer tubular element, the inner tubular element being slidable in the outer tubular element along the pusher direction.
 9. The drum conveyor according to claim 1, wherein the mechanical coupling between the first shaft and second shaft and the pusher comprises a rack and a pinion.
 10. The drum conveyor according to claim 9, wherein the pusher comprises a first rack and a second rack, and the first shaft comprises a first pinion and the second shaft comprises a second pinion; the pusher being positioned so that the first rack engages with the first pinion and the second rack engages with the second pinion.
 11. The drum conveyor according to claim 1, wherein the linear movement of the pusher defines an amplitude and wherein the amplitude is so selected that the first seat and the second seat rotate at least of 90 degrees.
 12. The drum conveyor according to claim 1, comprising a plurality of N seats and a plurality of N shafts, and N/2 pushers, wherein each k-th, where k=1 . . . N/2, pusher of the N/2 pusher is coupled to two nearest neighbour shafts (i, i+1), where i=1, 3, 5 . . . N−1 according to one or more of the preceding claims.
 13. A system for turning rod-shaped articles, the system comprising: a drum conveyor according to claim 1; an inspection apparatus adapted to inspect rod-shaped articles positioned on the first seat or on the second seat.
 14. A method to rotate rod-shaped articles having a longitudinal axis, the method comprising: providing a drum conveyor defining a drum rotational axis and an outer peripheral surface, the drum conveyor comprising: a first seat and a second seat located at the outer peripheral surface of the drum conveyor; a first shaft and a second shaft, wherein the first shaft defines a first shaft longitudinal axis and the second shaft defines a second shaft longitudinal axis, the first shaft longitudinal axis and the second shaft longitudinal axis being substantially perpendicular to the drum rotational axis, the first seat being attached to the first shaft and the second seat being attached to the second shaft; a pusher forming a mechanical coupling with the first shaft and the second shaft; positioning a rod-shaped article in the first seat and in the second seat; rotating the drum conveyor around the drum conveyor rotational axis; moving the pusher linearly along a pusher direction while rotating the drum conveyor; transforming the linear movement of the pusher into a rotational movement of the first shaft and of the second shaft around the first shaft longitudinal axis and the second shaft longitudinal axis so as to rotate the longitudinal axes of the rod-shaped articles in the first seat and second seat.
 15. The method according to claim 14, wherein the step of rotating the drum conveyor comprises: rotating the drum conveyor around the drum rotational axis by 360 degrees; and wherein, in the same 360 degrees rotation of the drum conveyor, the step of rotating the first shaft and the second shaft comprises: rotating the first shaft and the second shaft from a configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are perpendicular to the drum rotational axis to a configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis; rotating the first shaft and the second shaft from the configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis back to the configuration where the longitudinal axes of the rod-shaped articles in the first seat and in the second seat are parallel to the drum rotational axis. 